| 摘要 |
PURPOSE:To produce an ultra-low iron loss grain-oriented electrical steel sheet which maintains the initial effect even after a heat treatment such as stress relief annealing by removing the surface film of the grain-oriented electrical steel sheet subjected to finish annealing then forming a film of an infilterable material on the steel sheet and subjecting the steel sheet to stoving and heat treatment. CONSTITUTION:The surface film such as slag film, oxide film and insulating film formed on the grain-oriented electrical steel sheet subjected to finish annealing is removed from the entire surface or at intervals by pickling, shot blasting, etc., to expose the base metal of the steel sheet. The film of the infilterable material such as metal, non-metal, oxide or salt is formed by coating, etc., on the steel sheet and, if necessary, the steel sheet is strained before and/or after the above-mentioned film formation. The above-mentioned film is then fired and is securely stuck to the base metal of the steel sheet. The steel sheet is thereafter subjected to the heat treatment to bring the infilterable material forming the film into reaction with the base metal of the steel sheet to form the infiltered material by which the magnetic segmentation having heat resistance is stably executed to a high degree. The grain-oriented electrical steel sheet which maintains the improving effect of iron loss even after the heat treatment such as stress relief annealing and has the extremely low iron loss is thus obtd. |
